-LRB- CNN -RRB- -- Investigators probably will have to use dental records to identify some of the eight people who were killed in a wreck involving a church bus and two other vehicles in eastern Tennessee , a Tennessee Highway Patrol official said Thursday .

Some of the bodies in Wednesday 's crash were burned or otherwise made unrecognizable , hindering authorities ' ability to notify all of the victims ' families about the deaths , highway patrol Sgt. Bill Miller said .

`` The crash is so horrific ... it 's probably the worst that I have seen in my career ... and I 've worked in several , several counties in my '' 17 years on the job , Miller said .

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The bus , owned by a North Carolina church , was carrying a group of seniors on their way back home from a religious conference when one of its tires malfunctioned , sending the bus across a median on Interstate 40 and crashing into an SUV and a tractor-trailer , authorities said .

Church bus was carrying seniors home from a jubilee

Eight people were killed : Six on the eastbound bus ; one of three occupants of the SUV , and the tractor-trailer driver , the Tennessee Highway Patrol said .

Two of the 14 other people who were hospitalized after the wreck had been released by Thursday morning , said Travis Brickey , a representative of the University of Tennessee Medical Center .

Two people were in critical condition ; seven were in serious condition , and three were in stable condition , Brickey said . None of the victims ' names was released .

The church group -- about 18 people including the driver , Miller said -- was returning to the Front Street Baptist Church in Statesville , North Carolina , after attending the 17th annual Fall Jubilee conference in Gatlinburg .

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The group of senior citizens was called `` Young at Heart , '' said Rick Cruz , the church 's pastor .

Twelve of the hospitalized victims -- including the two in critical condition -- are church members , Cruz said Thursday morning .

`` It 's been a very long night for all of us here , '' Cruz told reporters . `` We are thankful for all the prayers and support that we 've been receiving . ''

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The wreck happened about 2 p.m. Wednesday in Jefferson County , about 40 miles east of Knoxville , the Tennessee Department of Safety said .

Miller said it was n't clear exactly what happened to the bus tire , other than it malfunctioned or failed in some way .

The bus swerved across a grassy median and struck the SUV before hitting the tractor-trailer , he said . The bus came to rest on its side , pinning some of its occupants , he said .

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Video from the site showed smoke rising from the tractor-trailer . Some people walked out of the bus on their own , but emergency personnel had to extricate others , Miller said .

`` This was such a horrific crash that determining if seat belts were used or not ... may be extremely difficult to impossible to determine , '' he said .

Miller said it 's too early to know whether charges will be filed in connection with the wreck .

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CNN 's Andrew Spencer and Rich Phillips contributed to this report .

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NEW : Two of the 14 people hospitalized have been released

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Eight killed , 14 others injured in three-vehicle wreck on I-40

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North Carolina church bus carried seniors returning from Tennessee jubilee

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Police : Tire failed and bus crossed the median , striking an SUV and a tractor-trailer